Regarding MA withdrawal symptoms, our result showed that females were more likely to experience MA withdrawal symptoms (but not greater withdrawal severity), a finding that is partly consistent with another prior MA inpatient study (He et al., 2013). The difference between studies were that ours found the withdrawal symptoms more common in females were hypersomnia, fatigue and psychomotor retardation, whereas He's study found chilly feeling and sweating were more common in females. However, these differences may be accounted for by the differences in symptoms ascertained. Ours used criteria from the SSADDA, which are more specific to MA withdrawal (e.g. depressed mood, hypersomnia, increased appetite, psychomotor retardation); the other study's criteria did not include all of these symptoms (He et al., 2013). Instead, they used 16 general criteria for substance withdrawal such as chilly feeling, sweating, runny nose, palpitation or insomnia. Although the biological mechanisms underlying sex differences in MA withdrawal are unknown, the higher rate of MA-withdrawal in females may be related to the heavier MA use observed in dependent females.
